Of the many electrical wires that constitute a wire harness, the plurality of electrical wires that require circuit connection are stripped of their sheathed portion at their electrical wire terminals, and the exposed core wires are resistance welded, ultrasonically welded, or crimped together to form a terminal consolidation splice (hereinafter referred to as “splice portion”). Insulation protection is required because a short circuit occurs when the splice portion comes into contact with another conductive material, and water sealing processing is required because corrosion occurs if water adheres to the splice portion, particularly if the splice portion is to be arranged in a submersion area. As shown in FIG. 6, the protecting cap is a bottomed tubular protecting cap 100 that is made of resin, and is filled in advance with a melted water sealant 110 using a nozzle 120, then a terminal consolidation splice 210 of a wire harness 200 is inserted into the protecting cap 100 via an insertion hole 101, and the water sealant 110 is cured. (see JP 2000-324671A and Japanese Patent JP 2008-313846A).
In the protecting cap filled with the water sealant, there is a need to reliably submerge in the water sealant 110 a required range including the splice portion 210, a stripped portion 200a that is continuous with the splice portion 210, and a sheathed portion 200b that is continuous with the stripped portion. For this reason, the filling amount of the water sealant 110 is set based on the relation between the size of the protecting cap 100 (cross-section surface area and length) and the volume of the splice portion 210, the stripped portion 200a, and the sheathed portion 200b. 
As shown in FIG. 7, as specific criteria, it is necessary to position a tip surface 210s of the splice portion 210 within 3 mm from an inner surface 100i of a closed bottom 100a of the protecting cap 100, and to submerge at least 1 mm of the sheathed portion 200b with the water sealant 110.
If the splice portion 210 is inserted into the protecting cap 100 that has been filled with the water sealant 110 in advance, the splice portion 210 is likely to float up due to the water sealant 110. Thus, there are cases where the splice portion 210 is distanced from the closed bottom 100a of the protecting cap 100, and the required range of the sheathed portion 200b is not submerged in the water sealant. Also, if the volume of the splice portion 210, the stripped portion 200a, and the sheathed portion 200b of the electrical wire group that is continuous with the splice portion inserted into the protecting cap 100 changes even marginally, the level of the water sealant 110 that has been filled into the protecting cap 100 changes, and there is the concern that the water sealant will spill out from the insertion hole 101 in the protecting cap 100 and liquid leakage will occur.
Accordingly, even if the protecting cap 100 is filled with a set amount of the water sealant 110, after the splice portion 210 has been inserted into the protecting cap 100 and the water sealant has cured, there is a need to examine the manufactured product as to whether the above-described range including the splice portion 210 and the like is submerged in the water sealant 110. For this reason, conventionally, a worker used to apply a ruler to the outside thereof and perform an examination.